In performing printing with a network printer that is an example of a network device, when a host terminal of a user is present in a location apart from the network printer, it, is likely that a content of a print is seen by others until the user reaches the network printer. This causes a problem when the user prints a confidential document that the user does not desire to be seen by others. Therefore, it is demanded to provide a security function in the network printer.
Conventionally, as a technique for improving security for the network printer, for example, a printing apparatus disclosed in a patent document 1 and an image output apparatus described in a patent document 2 are known.
In the invention described in the patent document 1, first, the printing apparatus judges whether a print job received from a host terminal is a normal print job or a spool print job. When it is judged that the print job is a spool print job, the printing apparatus expands the print job into output data and stores the output data expanded in a storage together with job designation information. Then, when a user inputs job designation information, the printing apparatus specifies a print job, which should be performed, from plural print jobs stored in the storage on the basis of the job designation information inputted. The printing apparatus reads out output data of the print job specified and performs printing.
In the invention described in the patent document 2, first, a host terminal transmits an authentication code to a printer server together with print data. The printer server generates data for collation from the print data received, encrypts the received print data with the authentication code to generate storage data, and stores the storage data and the data for collation in a storage in association with each other. When a user selects the storage data with a UI unit and inputs the authentication code, the printer server decrypts the storage data with the authentication code as a key and judges whether the storage data could be decrypted correctly with reference to the data for collation. If the storage data could be decrypted correctly, the printer server causes a print engine to print a result of the decryption.
However, in the inventions described in the patent documents 1 and 2, there is a problem in that, when the user wishes to change a print destination after the host terminal transmits a print job or print data, the user has to delete the print job or the print data and then perform the transmission again, which requires time and labor. Thus, a print system described in a patent document 3 is proposed as a technique that allows a user to arbitrarily change a print destination even after a print job or print data is transmitted.
In an invention described in the patent document 3, a host terminal transmits print data and a password to a printer server. A network printer transmits a password and a job number inputted to an image input apparatus to the printer server. The printer server transmits, after performing authentication, the print data to the network printer to cause the network printer to print an image.
In an invention described in a patent document 4, a print job received from a host terminal at a request source of the print job is transferred to a network printer serving as a transfer destination set in advance. When an NW board of the network printer detects PDL analysis abnormality or occurrence of jam or the like in a printing engine unit through communication with a PDL board, the NW board instructs the network printer serving as the transfer destination to start page analysis processing for the print job.    [Patent Document 1] JP-A-4-364971    [Patent Document 2] JP-A-2001-306273    [Patent Document 3] JP-A-2003-140875    [Patent Document 4] JP-A-2002-189578
In the invention of the patent document 3, print data is held by the printer server on a network. Thus, there is a problem in that the print data is likely to be stolen because of illegal access or the like while the printer server holds the print data.
If the inventions described in the patent documents 1 and 2 are applied to the invention described in the patent document 4, it is possible to perform confidential printing while improving a degree of freedom of changing a print destination.
However, in such a combination, as in the invention of the patent document 3, print data is held by each printing apparatus that is likely to execute print processing on a network. Thus, there is a problem in that the print data is likely to be stolen because of illegal access or the like until printing is started after the printing apparatus or the like holds the print data.
Such a problem is anticipated not only in the case in which printing is performed by a network printer but also in the case in which, for example, a display device such as a projector or an LCD (Liquid Crystal Display) is connected to a network and display is performed by the display device. In other words, when an image or the like is displayed using the projector, the LCD, or the like, even if image data (video data) or the like is held in a server or the like and taken out and displayed when necessary, data is likely to be stolen because of illegal access or the like while the data is held in the server or the like.
Thus, the invention has been devised in view of such unsolved problems inherent in the conventional techniques and it is an object of the invention to provide an output system, a network device, a device using apparatus, an output control program and an output request program, and an output method that can improve a degree of freedom of changing an output destination and improve security for output data.